A winder of present day construction for continuously winding web material into rolls is usually equipped with roll changing apparatus which is manually or automatically actuated to cut the web between a fully wound roll and an empty core, and to effect a connection between the resulting cut leading end of the web and the core that will cause the web to start winding on the new core.
It is highly desirable that this operation of roll changing be carried out in such manner that there is minimum possibility of the cut leading end portion of the web folding on itself and creating a ridge on the core over which subsequent layers of web material are wound. For example, when the web is attached to the core by a strip of adhesive tape prelaid on the core, it is important that there be a minimum amount of web between the cut leading end of the web and the strip across the web which is attached to the new core, to prevent fold-back of that leading end of the web. A zero fold-back start of each new roll is especially important with stretchable web materials, such as stretch wrap and shrink wrap plastics, because fold back on the new core can cause bulges in the roll which seriously affect the quality of the web material for subsequent use.
One of the factors affecting the start of each new roll on a core is the method or means by which the web is cut in the course of roll changing. It is common to use a knife for this purpose, such particularly as a serrated blade, and typical examples of knives for this purpose are shown in the co-owned U.S. Pat. Nos. to Phelps et al. No. 3,841,577 and No. 4,326,679, and Tetro No. 4,422,586.
In the apparatus of each of those patents, some means are required for aiding the knife in causing the cut leading end of the web to begin winding on the new core. Thus in U.S. Pat. Nos. 3,841,577 and 4,422,586, each core must be "prepared" by being provided with a strip of adhesive extending lengthwise thereof to which the web will adhere, and in U.S. Pat. No. 4,326,679, a curved shoe guides the cut leading end of the web directly from the knife into the nip between the new core and the pressure roll.
It is also old and well-known in the web handling arts, including the making and handling of paper webs, to employ water jets for slitting or otherwise cutting the continuously moving web. Nevertheless, it is believed to be novel to employ water jets in roll changing apparatus for a continuous winder as described hereinafter.